#### Answer

$$mean = 1.5$$
$$median = 1.5$$
$$mode = none$$

#### Work Step by Step

To calculate the mean, sum the data values in the set and divide by the number of data values in the set:
$$mean = \frac{1.2+1.3+1.4+1.5+1.6+1.7+1.8}{7}=\frac{10.5}{7}=1.5.$$
The median is the middle value of the data set when it is arranged in increasing or decreasing order:
$$1.2,1.3,1.4,1.5,1.6,1.7,1.8.$$
So
$$median = 1.5.$$
The mode is the value which occurs most often in the data set. Since all the values appear only once, there is no mode in this case.